Airbag structure

ABSTRACT

A strong lightweight airbag cushion for deployment in opposing relation to a vehicle occupant is provided. The cushion is formed from a body of wound yarn. The body includes an interior, a face portion for contact with the occupant and a rear portion including an inlet port for the introduction of an inflation medium. The body is formed by the continuous winding of yarn around a mandrel such that the yarn is spread across the face and is disposed preferentially across the back in the area surrounding the inlet port so as to provide added strength in that region.

FIELD OF THE INVENTION

The present invention relates to inflatable protective cushions, andmore specifically relates to a cushion formed by the highly efficientcontinuous winding of yarn. The cushion is particularly useful in thefrontal or side protection of occupants in a transportation vehicle,such as an automotive vehicle, railroad, car, airplane or the like. Aprocess for forming the cushion and an optimum shape for the cushionaccording to the present invention are also provided.

BACKGROUND

Inflatable protective cushions used in passenger vehicles are acomponent of relatively complex passive restraint systems. The mainelements of these systems are: an impact sensing system, an ignitionsystem, a propellant material, an attachment device, a system enclosure,and an inflatable protective cushion. Upon sensing an impact, thepropellant is ignited causing an explosive release of gases filling thecushion to a deployed state which can absorb the impact of the forwardmovement of a body and dissipate its energy by means of rapid venting ofthe gas. The entire sequence of events occurs within about 30milliseconds. In the un-deployed state, the cushion is most commonlystored in or near the steering column, the dashboard, in a door panel,or in the back of a front seat placing the cushion in close proximity tothe person or object it is to protect.

Inflatable cushion systems commonly referred to as airbag systems havebeen used in the past to protect both the operator of the vehicle andpassengers. Systems for the protection of the vehicle operator havetypically been mounted in the steering column of the vehicle and haveutilized cushion constructions directly deployable towards the driver.These driver-side cushions are typically of a relatively simple sewnconfiguration. Typically, traditional driver's side inflatable cushionshave been formed by sewing together two circular pieces of coated fabricmade of nylon or polyester yarn.

Although such sewn products have generally performed quite adequately,they nonetheless have some inherent limitations. First, the sewn seam isgenerally applied or at least inspected manually. As will beappreciated, this is a relatively time consuming process which tends toincrease manufacturing costs. Second, circular and elliptical cushionsformed by sewing around the perimeter are prone to wrinkles which mayresult in high and low stress concentrations thereby reducing themaximum inflation pressure which can be maintained at the seam. Third,the introduction of a sewn seam necessarily gives rise to small openingsfor the sewing threads. These openings tend to act as an escape path forthe inflation gases within the airbag which may lead to seam slippage orso called “combing” of the seam thereby giving rise to a potentialmechanism for failure. Fourth, even after the two disk shaped componentsare sewn together, the area surrounding the gas introduction port (i.e.the mouth) must generally be reinforced with additional layers of fabricreferred to as doublers so as to control the large forces applied inthis area during an inflation event. As will be appreciated, theaddition of these doublers gives rise to additional manual processingand the need for additional fabric. Finally, the use of substantiallycircular shapes results in substantial material waste duringmanufacturing due to the inherent inability of the manufacturer to cutdisk patterns in close-packed spacing arrangement.

Various alternative sewn constructions have been proposed such as thosedisclosed in U.S. Pat. No. 5,482,317 to Nelsen et al; U.S. Pat. No.5,520,416 to Bishop; U.S. Pat. No. 5,454,594 to Krickl; U.S. Pat. No.5,423,273 to Hawthorn et al; U.S. Pat. No. 5,316,337 to Yamaji et al;U.S. Pat. No. 5,310,216 to Wehner et al; U.S. Pat. No. 5,090,729 toWatanabe; U.S. Pat. No. 5,087,071 to Wallner et al.; U.S. Pat. No.4,944,529 to Buckhaus; and U.S. Pat. No. 3,792,873 to Buchner (allincorporated herein by reference). However, these constructions eachrely on some seaming of precut fabric panels and thus exhibit some ifnot all of the limitations outlined above.

The manufacture of airbag cushions by means of winding yarns andtape-like materials around a mandrel has been proposed in severalpublications including Japan Kokai Patent document 3-227751 in the nameof Kanuma and Japan Kokai Patent document 3-276845 in the name of Ogamiet al. (both incorporated herein by reference).

While these referenced publications recognize many of the limitationsinherent in traditional sewn airbags, and have broadly proposed the useof winding technology as a means to avoid those limitations, theynonetheless fail to provide a highly efficient practice for the properdistribution of yarn. Rather, the prior art in this area has reliedgenerally upon the winding of broad, tape like structures or of arelatively large number of parallel yarns to achieve the substantiallycomplete coverage of the cushion surface area. The prior art also failsto teach the ability to preferentially distribute yarns in the areasurrounding the inlet opening so as to provide additional support inthis area thereby substantially reducing or eliminating the need for theapplication of an additional reinforcement in this region.

The airbag according to the present invention is formed from yarn whichis substantially evenly distributed across the face of the cushionthereby avoiding the accumulation of yarn and the ultimate developmentof a nodule of undue thickness at the center of the cushion where impactwith an occupant is likely to occur. In addition, the yarn is disposedin such a manner that a thickened ring of yarn is built up around theinflation opening thereby enhancing the strength of the cushion at thevery location where reinforcement is generally required. The airbagaccording to the present invention thus provides a useful advancementover the present art.

SUMMARY OF THE INVENTION

In view of the foregoing, it is a general object of at the presentinvention to provide an easily manufactured seamless airbag cushion.

It is a more particular object of the invention to provide a seamlessairbag cushion formed by the winding of yarn about a removable mandrelsuch that the yarn is substantially evenly distributed across the faceof the cushion.

It is a further object of the present invention to provide a seamlessairbag cushion formed by the winding of yarn about a removable mandrelsuch that the yarn is disposed preferentially across the back of thecushion in the area surrounding the inlet port so as to form a localizedregion of enhanced thickness to provide additional strength in thatregion surrounding the inlet port.

It is a further potential object of the present invention to provide aseamless airbag cushion formed by the winding of yarn about a removablerotating mandrel wherein the cushion includes a flexible permeabilityblocking layer of material holding the yarn in place.

An additional object of the invention is to provide a low costinflatable protective cushion of simple and structurally efficientdesign with a shape and construction that optimizes the cushion'sability to withstand inflation pressure and impact when deployed.

It is a preferred feature of the present invention to provide a seamlessairbag cushion formed by the winding of a yarn in a continuous fashionaround a generally spheroidal rotating mandrel while systematicallyshifting the angle of placement of the yarn with respect to the axis ofrotation of the mandrel about a point near the mouth of the bagstructure being formed such that a localized region of enhancedthickness is formed around the mouth opening.

It is yet a further potentially preferred feature of the presentinvention to provide a seamless airbag cushion formed by the winding ofa yarn in a continuous fashion around a generally spheroidal rotatingmandrel having a shape substantially similar to the desired shape of thefinished cushion wherein the ratio of the depth of the cushion to itsequatorial diameter is about 0.5 to 0.7.

Additional objects and advantages of the invention will be set forth inpart in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention will be realized and attained bymeans of the elements and combinations particularly pointed out in thewritten description and claims as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings which are incorporated in and constitute apart of this specification, serve to illustrate several preferredembodiments and practices according to the present invention andtogether with the description, serve to explain the principles of theinvention wherein:

FIG. 1A is a cutaway view of an inflatable cushion according to thepresent invention and inflation module housed within the steering columnof a vehicle.

FIG. 1B illustrates a cutaway view of an inflatable cushion according tothe present invention in deployment between a passenger and the steeringcolumn.

FIG. 2 illustrates the yarn winding operation for forming the airbagaccording to the present invention.

FIGS. 3-5 are plan views of the airbag winding operation carried outaccording to the potentially preferred practice of the presentinvention.

FIGS. 6A and 6B are, respectively, elevation views of the rear and frontof an airbag cushion formed according to the potentially preferredpractice of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

Reference will now be made in detail to potentially preferredembodiments and practices. It is, however, to be understood thatreference to any such embodiments and practices is in no way intended tolimit the invention thereto. On the contrary, it is intended by theapplicants to cover all alternatives, modifications and equivalents asmay be included within the spirit and scope of the invention as definedby the appended claims.

Airbags may be produced from a number of different materials using amultiplicity of techniques. However, commercially acceptable airbagshave heretofore typically been formed, at least in part, from some typeof woven textile material. By way of example only and not limitation,such textile materials are disclosed in U.S. Pat. No. 5,503,197 to Boweret al.; U.S. Pat. No. 5,477,890 to Krummheuer et al.; U.S. Pat. No.5,277,230 to Sollars, Jr.; U.S. Pat. No. 5,259,645 to Hirabayashi, etal.; U.S. Pat. No. 5,110,666 to Menzel et al.; U.S. Pat. No. 5,093,163to Krummheuer et al.; U.S. Pat. No. 5,073,418 to Thornton et al.; U.S.Pat. No. 4,921,735 to Bloch; and U.S. Pat. No. 3,814,141 to Iribe et al;(all incorporated herein by reference).

A typical airbag deployment system 10 for use in opposing relation tothe driver of a vehicle is illustrated in FIG. 1A. In general, similarequipment is used in passenger and side protection devices, although thegeometry of the components therein may vary. The airbag deploymentsystem 10 generally comprises an inflator 12, an inflatable cushion 14which includes a mouth portion surrounding the inflator 12 therebypermitting the cushion to be inflated by gas released from the inflatorduring a collision event. The cushion 14 and inflator 12 are typicallyhoused beneath a frangible cover 16 which breaks open along a notch 18of reduced thickness during the deployment event. As illustrated in FIG.1B, upon deployment the cushion 14 is in a position to receive a vehicleoccupant 20. As will be appreciated, the kinetic energy of the occupant20 is dissipated by the collapse of the cushion 14 as gas is releasedeither through inherent permeability of the material forming the cushion14 and/or through internal pressure sensitive vents 22. The cushion 14may further include shape controlling tethers 24 which require thecushion to expand to a pre-determined desirable geometry upon inflation.

In FIG. 2 a side view of the apparatus 30 for carrying out the yarnwinding operation according to the present invention is illustrated. Asshown, the apparatus 30 preferably includes a rotatable platform 32 forholding one or more packages 34 of yarn 36 for use in formation of theairbag according to the present invention. The yarn 36 is preferablywrapped around a spool 38 such that the yarn may be removed in acontinuous fashion without the occurrence of tangling. While multiplepackages 34 are illustrated, it is to be understood that the presentinvention does not require the delivery of more than one continuous yarn36 in order to achieve effective bag formation. When the operation iscarried out with a single continuous yarn, the use of multiple packageshas the advantage of avoiding frequent package replacement since thepackages are already in place.

While the invention contemplates the use of a single yarn in the windingoperation, it is likewise contemplated that two or more yarns 36 may bedelivered and wrapped simultaneously in substantially side by siderelation to one another during the winding operation. It is furthercontemplated that the yarns 36 and each of the packages 34 may be eitherof the same or of a different character. Thus, if an individual yarn 36is to be wound according to the present invention the initial stages ofthe winding operation may be carried out using one type of yarn whilethe latter stages may be carried out using yarn of differing character.Likewise if two or more yarns 36 are to be wound simultaneously, it iscontemplated that these yarns may be either of the same or differingcharacter. As will be appreciated this ability to select combinations ofyarns having different character may be of value in exploiting thebenefits of various different yarn combinations within the structure tobe formed.

In the illustrated and potential preferred practice, the yarn 36 isdelivered to a central eye 40 for subsequent transmission through atubular guide path 42 for eventual delivery through a balanced hollowarm rotating winding apparatus 46.

The winding apparatus 46 is preferably a symmetrical structure having atleast two yarn delivery arms 48,50 extending outwardly from either endof an elongated support shaft the center of which preferably serves asthe axis of rotation for the winding apparatus 46. As shown, the windingapparatus may also include one or more additional arms 49 preferablydisposed in balanced relation to the other arms. In one potentiallypreferred embodiment, the winding apparatus will have four hollowsymmetrically disposed yarn delivery arms each of which deliver aseparate yarn 36 from a separate package 34.

In the preferred embodiment, the winding apparatus 46 is preferablyrotated about the axis of rotation 54 by means of a variable speed motor56 controlled by a computer (not shown) or other control means as areknown to those of skill in the art such that the rate of winding andnumber of revolutions may be preset and closely monitored during thewinding operation.

The yarn 36 which is delivered through the hollow winding apparatus tothe end of at least one of the yarn delivery arms is initially securedin place against a collapsible mandrel 60 by either a small piece ofadhesive tape or by manually wrapping one or two loops around themandrel such that frictional forces prevent the yarn from pulling away.Thereafter, the mandrel 60 rotated by means of its own independentvariable speed motor 62 (FIG. 3) while simultaneously rotating thewinding apparatus 46 such that the yarn 36 is continuously drawn fromthe winding apparatus around the mandrel. As will be appreciated, bycontrolling the rotation of both the mandrel 60 and the windingapparatus 46, substantial control can be exerted over the final yarndistribution.

The mandrel 60 is preferably covered at least in part by a thinreleasable film of a material such as PVC, polypropylene, polyamide,polyurethane or the like to permit separation of the yarns 36 from themandrel 60 following application of a permeability blocking coatinglayer as described below. In one particularly preferred embodiment, thereleasable film is disposed across the surface of the mandrel 60corresponding to the front of the cushion 14 against which the occupant20 would be thrown, while the rear surface is wound without a releaselayer. This practice provides the dual advantage of minimizing theamount of release film utilized while at the same time providing anadded barrier layer between the occupant and the inflation gases whichare generally hot and may carry particulates

As best illustrated in FIGS. 3-5, the mandrel 60 is preferably of ashape substantially corresponding to the final desired shape of theairbag cushion being formed. While any shape susceptible to rotation andyarn coverage may be utilized, it is contemplated that circular andellipsoidal spheroids may be particularly preferred for driver's sideairbag cushions.

The mandrel 60 itself is necessarily of such a nature that it can beremoved from the final airbag structure after formation is complete.Materials which may be particularly well suited to this purpose includesculpted foam rubber, collapsible segmented metal structures, anddurable textile structures formed from material such as KEVLAR® or thelike which may be held in an inflated state under modest gas pressuresthrough connection to an air line during the processing sequence. Asshown, the mandrel 60 is preferably connected to a hub 64 disposed alongits axis of rotation. In the illustrated and potentially preferredpractice, the placement and diameter of the hub 64 defines the size andlocation of the inlet port in the final airbag cushion.

As will be appreciated by those in skill of the art, the regionsurrounding the inlet port serves as the location of connection betweenthe inflatable cushion 14 and the inflator 12 (FIG. 1A) and must,therefore, withstand significant stress during a deployment event. Thesestresses can be overcome by providing enhanced thickness of the cushionin this localized region.

It has been found that by orienting the mandrel 60 relative to thewinding apparatus 46 such that the yarn placement plane 66 (as definedby the outlet of the yarn delivery arms) runs immediately adjacent tothe hub 64, that it is possible to obtain the desired increasedthickness in the region immediately surrounding the mouth with graduallydecreasing yarn concentration as the distance from the mouth isincreased. This preferential yarn concentration is illustrated in FIG.6A wherein the gas inlet 70 disposed within the rear portion of thecushion 14 is surrounded by a relatively thick collar of material whichdecreases in concentration as the distance from the center is increased.That is, the number of yarns per unit area decreases as the perimeter ofthe cushion is approached.

Aside from the desire to enhance the strength of the cushion in the areasurrounding the inlet port 70, it is a further attribute of the cushionaccording to the present invention to avoid a preferential accumulationof yarns at the face of the inflatable cushion since such a build upgives rise to the formation of a generally undesirable hard nodule onthe surface which is to be impacted by the vehicle occupant 20 during acollision event. It has been found that when the yarn 36 is wrappedaround the rotating mandrel 60 while maintaining a fixed angle Φ betweenthe yarn placement plane 66 (FIG. 3) and the equatorial plane 72 of themandrel, that each winding tends to cross over the prior windings withina relatively small localized location on the face of the inflatablecushion 14 which thereby causes the undesirable build-up of a thicknodule of yarn in this location on the face. Such a build-up of yarn is,of course, exactly what is desired in the region surrounding the inletport 70 on the rear portion of the cushion 14.

It has been found that these seemingly conflicting goals ofconcentrating the yarn around the inlet port on the rear of the cushionwhile at the same time spreading the yarn substantially evenly acrossthe face may be achieved by systematically shifting the angle of theyarn placement plane 66 with respect to the equatorial plane 72 of therotating mandrel 60 about a pivot point selected such that the yarnplacement plane 66 continues to fall substantially adjacent to the hub64 on the rear portion of the rotating mandrel 60. This systematicshifting of the yarn placement angle is best illustrated throughreference to FIGS. 3-5 wherein in FIG. 3 the yarn placement plane 66 isat a first angle Φ with respect to the equatorial plane 72 of themandrel. In FIGS. 4 and 5 this angle is gradually increased until thetwo planes are nearly perpendicular.

In the illustrated and potentially preferred practice of the presentinvention, shifting of the yarn placement plane is effected by pivotingthe winding apparatus 46 about a pivot 80 (FIG. 2) through use of anextensible and retractable power cylinder 82 acting on the support forthe winding apparatus. In the illustrated and potentially preferredpractice, the pivot 80 is placed such that its center is aligned justoutside the outer perimeter of the hub 64 which serves to define theinlet port 70. As a power cylinder 82 is retracted from its fullyextended position in FIG. 3 through an intermediate position in FIG. 4to a fully retracted position in FIG. 5, the yarn placement on the frontof the mandrel 60 is substantially changed. However, due to theselection of the pivot point location, the yarn placement on the rear ofthe mandrel is not significantly altered. Thus, the seeminglycontradictory need to concentrate yarn around the inlet port whilesimultaneously spreading yarn across the face can be met. Moreover,since the power cylinder 82 may be cycled by the computer or othercontrol means independently from the rotation of the mandrel and thewinding apparatus, the pivoting action provides the operator with yetanother degree of freedom with which to control the manufacturingprocess.

While it is contemplated that a wide variety of combinations ofoperating parameters may be utilized to produce inflatable restraintcushions according to the present invention, by way of example only, andnot limitation, it is believed that in the preferred practice themandrel 60 should be rotated at a rate of about 0.05 to about 30.0revolutions per minute, the winding apparatus should be operated at arate of about 50 to about 600 revolutions per minute, the angle betweenthe yarn placement plane 66 and the equatorial plane 72 should be cycledbetween about 46° and about 90° with about 1 to about 20 full cycles ofextension and retraction of the power cylinder 82 per minute.

While it is likewise contemplated that any number of different types ofyarns 36 may be utilized, it is believed spun or filament polymericyarns formed from fiber materials such as polyester, nylon 6, nylon 6.6,nylon 4.6, KEVLAR® and SPECTRA® characterized by yarn linear densitiesin the range of about 40 to 1200 denier (preferably about 70 to 200denier) and filament linear densities in the range of about 2 to 6denier per filament (preferably 3 to 5 denier per filament) may bepreferred. The average yarn concentration as measured by dividing thetotal mass of yarn utilized in a given bag by the surface area for thatbag including regions of both low and high yarn concentration ispreferably in the range of about 50 to 300 grams per m².

As will be appreciated, in some instances, the concentration of yarnitself may not be sufficient to block air flow. In addition, the releasefilm which is carried with the cushion is preferably of a very lightweight character and may not provide complete porosity blockingperformance. Moreover such release films may be completely absent if themandrel is of such a nature that a release layer is unnecessary. By wayof example only, it is contemplated that a mandrel formed of a textilematerial coated with Teflon, silicone or other adhesion resistantmaterial may make the use of a release layer unnecessary. Accordingly,in one potentially preferred practice it is desirable to apply aporosity blocking coating of material across the wound yarn structure soas to hold the yarn in place and to provide containment for the gaseousinflation media generated during an expansion event. While any number ofcoating materials may be utilized, it is required that such material beflexible in nature such that it can span the voids between the yarnswithout failing under pressure. It is believed that thermoplastic orthermosetting compositions of polyurethane, polyamide, polypropylene,PVC, acrylics and mixtures of these materials may be useful. Thesematerials may be applied by spray coating, knife coating, dip coating orother commercial processes as may be known to those of skill in the art.By way of example only, it is believed that the weight concentration ofthe elastomer in the final bag may be in the range of about 40 to 900grams per m².

As previously indicated, aside from a fundamental formation technique,the present invention further contemplates a potentially preferred shapefor the inflatable cushion 14 so as to optimize the strengthcharacteristics of the load bearing yarns 36 within the structure.Hence, this optimized shape characteristic would be used in the designof the mandrel 60 for use in the winding procedure described above.

It is believed that the maximum strength of a composite material such asthe wound airbag structure of the present invention is obtained when thestrains in the individual components are matched. Thus, the optimumshape for maximum strength in the airbag of the present invention isobtained when there is uniform tension in the yarns. It has beendiscovered that the shape which results in uniform tension in the yarnsis a geometric curve which can be characterized parametrically incylindrical coordinates for one quadrant by the equations:$\frac{z}{a} = {\int_{0}^{\theta}{\frac{( {\sin ( {\frac{\pi}{2} - u} )} )^{(\frac{1}{2})}}{2}{u}}}$$\frac{r}{a} = {{{\sin ( {\frac{\pi}{2} - \theta} )}^{\frac{1}{2}}\quad 0} \leq \theta \leq \frac{\pi}{2}}$

Where r is the radial coordinate and z is the axial coordinate.

The radius at the equator is given by the equation:$a = \lbrack \frac{V}{2 \cdot \pi \cdot {\int_{0}^{\frac{\pi}{2}}{{{\sin ( {\frac{\pi}{2} - \theta} )} \cdot \frac{( {\sin ( {\frac{\pi}{2} - \theta} )} )^{(\frac{1}{2})}}{2}}{\theta}}}} \rbrack^{\frac{1}{3}}$

or approximately $a = {{.714} \cdot V^{\frac{1}{3}}}$

Where V is the desired volume of the bag at low inflation pressure.

The height to equatorial diameter (2a) ratio is:$\frac{2 \cdot h}{2 \cdot a} = {\int_{0}^{\frac{\pi}{2}}{\frac{( {\sin ( {\frac{\pi}{2} - u} )} )^{(\frac{1}{2})}}{2}{u}}}$

or approximately: $\frac{2 \cdot h}{2 \cdot a} = {.599}$

It is believed that the benefit of this shape in providing uniform yarntension is achievable in substantial respect so long as the radialcoordinate of the shape is within about plus or minus ten percent of itsideal value in relation to the other coordinates.

The following working example is presented to provide a more completeunderstanding of the invention. The specific techniques, conditions,materials, and reported data should be understood to be exemplary onlyand should in no way be construed as in way limiting the scope of theinvention which is intended to be defined and limited only by the fulllawful scope of allowed claims and equivalents thereto.

EXAMPLE

An inflatable round spheroidal rotating mandrel formed of KEVLAR®reinforced nylon film having an equatorial diameter of 22 inches and acentral depth of 11.75 inches was wrapped with a 1 mil thick film ofPT9611 Polyurethane and inflated to a pressure of 1 psi and rotated at arate of 0.322 revolutions per minute while a 112 denier multifilamentyarn of polyester having a denier per filament rating of 3.4 wasdelivered by a winding arm at a rate of 240 revolutions per minute for aperiod of 15.5 minutes. During the winding operation, the angle betweenthe plane of yarn placement and the equator of the mandrel was cycledfrom about 64.3 degrees to about 83.5 degrees and back every 0.134minutes. The total mass of yarn delivered around the mandrel was 2.36ounces over an area of 0.6836 square meters. An air line was used tomaintain the mandrel in an inflated state during the winding operation.While still under inflation, the mandrel and yarns wrapped thereaboutwere coated with an aqueous base polyurethane composition. The dried addon weight of the coating composition was 63.4 grams for the entirestructure. After drying, the sample was tested to failure by rapidlyexposing it to air heated to 1000° F. A pressure of 19.4 psi wasattained before the sample burst.

While specific preferred embodiments and materials have beenillustrated, described and identified, it is to be understood that theinvention is in no way limited thereto since modifications may be madeand other embodiments of the invention will occur to those of skill inthe art to which this invention pertains. Thus, it is intended to coverany such modifications and other embodiments ads incorporated thefeatures of this invention within the full lawful scope of the allowedclaims as follows.

What is claimed is:
 1. A strong lightweight airbag cushion fordeployment in opposing relation to a vehicle occupant during a collisionevent, the cushion comprising: a body of wound yarn including aninterior, a face portion for contact with the vehicle occupant and arear portion including an inlet port for the introduction of aninflation medium into the body, wherein the body is formed by windingsof yarn such that the yarn is evenly distributed across said faceportion of said body, and wherein at least some of said yarn crosses anequatorial plane between said face portion and said rear portion at anangle of between about 46° and about 90°, and such that the yarn isdisposed preferentially across the back of said body in the areasurrounding the inlet port so as to form a localized region of enhancedthickness around the inlet.
 2. The airbag cushion according to claim 1,wherein said body includes a flexible permeability blocking coating ofmaterial.
 3. The airbag cushion according to claim 2, wherein saidflexible permeability blocking coating of material is an elastomericadhesive.
 4. The airbag cushion according to claim 3, wherein saidelastomeric adhesive is applied across the surface of said cushion inthe form of a curable dispersion subsequent to the winding of said yarn.5. The airbag cushion according to claim 1, further comprising a filmdisposed across at least a portion of the interior of said body.
 6. Theairbag cushion according to claim 1, wherein said windings comprise oneyarn.
 7. The airbag cushion according to claim 6, wherein said one yarnis a yarn formed from polymeric materials selected from the groupconsisting of polyester, Nylon 6, Nylon 6.6 Nylon 4.6 and blendsthereof.
 8. The airbag cushion according to claim 6, wherein said oneyarn has a linear density in the range of about 40 to 400 denier.
 9. Theairbag cushion according to claim 1, having a generally spheroidalshape.
 10. The airbag cushion according to claim 1, further including aflexible, permeability blocking coating layer of elastomeric adhesiveholding the yarn in place.
 11. The airbag cushion according to claim 10,wherein said elastomeric adhesive is applied across the surface of saidcushion in the form of a curable dispersion subsequent to thesubstantially continuous winding of yarn.
 12. The airbag cushionaccording to claim 5, wherein said film is disposed across at least aportion of the interior of said face portion of said body.
 13. Theairbag cushion according to claim 5, wherein said film is disposedacross substantially the entire interior of said body.
 14. The airbagcushion according to claim 5, wherein said film is a thin releasablefilm.
 15. The airbag cushion according to claim 14, wherein said film isat least one of PVC, polypropylene, polyamide, and polyurethane.
 16. Amulti-layer airbag cushion, comprising: a body of wound yarn includingan interior, a face portion for contact with a vehicle occupant and arear portion including an inlet port for the introduction of aninflation medium into the body, a thin film disposed across at least aportion of the interior of said body, and a flexible permeabilityblocking coating over said body and film, wherein the body is formed bywinding at least one substantially continuous yarn over said film sothat at least some of said yarn crosses an equatorial plane between saidface portion and said rear portion at an angle of between about 46° andabout 90°, and then applying said blocking coating over said wound yarnand film.
 17. The multi-layer airbag cushion according to claim 16,wherein the film is polyurethane, the yarn is polyester, and the coatingis polyurethane.
 18. The multi-layer airbag cushion according to claim16, wherein said yarn of said body is evenly distributed across saidface portion of said body and the yarn forms a localized region ofenhanced thickness around the inlet.